Interesting, this is the first I've heard of substantial manufacture of novel, illicit firearms in Europe. Normally, the ease of access to mass-produced firearms on the black market would seem to eliminate this sort of private design. Replicating a mass-produced design in clandestine manufacture also reduces the risk of the clandestine manufacture being detected when the produced guns inevitably fall into the hands of police and other law enforcement.
Oh, and your Wikipedia link is mangled. The correct one is
Just use the part of the URL after the /wiki/ in the full URL inside the wiki tags, and always preview every post. It saves a lot of trouble.
Detection is likely, but finding and arresting them will be extremely difficult because 1) the machine and equipment from making guns have applications ranging from lawn mower parts to rocket engines, in short, the list is fucking huge 2) there are tons of machine shops and trying to monitor every single one of them would be a logistical nightmare 3) Some machine shop set ups are mobile (on top of huge diesel trucks) that is gonna add to difficulty, since it's a moving target 4) Even if governments order all computer aided machines to be installed with software to prevent gun parts from being made, there are always hackers and people to find ways around it. Not to mention that won't do jack shit against manually operated ones or ones that were built from stolen components.
I read that Croatia is the most likely suspect of it's origins, because it was know for cottage and clandestine weapons production during the the Yugoslav Wars, not unlike the weapons manufacturers in the Philippines and Pakistan.
A good example of this is the Agram 2000, another 9mm sub-machine gun that was produced clandestinely.Agram_2000
I believe that, we are seeing the beginning of technology rendering gun control obsolete. Twenty or thirty years ago a lathe or a mill would have costed several hundred grand even more so if it was CNC. Nowadays a DIY CNC lathe/mill set up can be as low as five grand. The only really tricky parts of a firearm to build is the barrel, magazine and the ammo, but with 3-d printing (polymer and metal) that is getting better, faster and cheaper every year, I think it is only a matter of time before gun control is rendered completely unenforceable.